Looking more like a made up animal than something from real life, the creature in question is a Siphonophore. In the order of Hydrozoa, it's actually a colony composed of many individual animals.

While this Siphonophore is particularly weird looking, a much better known species is the Portuguese Man o' War - or as we call it in Australia, the bluebottle. A Siphonophore is made up of zooids that are specilised to perform certain tasks. While they are individuals, they are so tightly integrated as one creature that many can no survive on their own.

The video was captured by the team exploring the oceans with the E/V Nautilius. They have a bunch of other cool videos of all manner of weird and wonderful sea creatures. If you want to know more check out the team or just watch the live feed.